1. Field of the Invention
The present invention relates to a method and apparatus for handling animal wastes from animals kept in cages with perforate bottoms.
2. Description of the Prior Art
When small animals are kept in cages in which the animals are not in contact with bedding, but rather are housed upon a wire mesh or otherwise perforate floor, animal wastes drop through the floor and into a litter tray beneath the cage which can be removed for cleaning. For hygenic and aesthetic reasons a substance is provided in the tray which will absorb or suspend liquid wastes and deodorize both liquids and solids, and which can be disposed of when soiled. Many bulk litter materials have been tried and have been used for this purpose, among them being shredded alfalfa, shredded aspen, shredded peat moss, wood shavings, and the like. Although these materials are absorbent, they are bulky, messy to handle, and often constitute a fire hazard in storage. Moreover, depending on the economic situation of the moment, they are often either expensive or unobtainable. Disposal of the solied litter, which often constitutes a considerable bulk, can be expensive, particularly in a vivarium. Soiled wastes are often imperfectly suspended in the solid litter. When the tray is emptied, some of the waste remains smeared on the tray. The next batch of litter will then be inoculated with oder-causing bacteria. To prevent this happening, each set of trays is commonly washed in a separate, remote facility, while clean trays from a second set are installed in the cages.
Commercial substitutes have been offered for the bulk litter recited above. One is a fibrous pad impregnated with substances which control odors and bacteria. Though easier to handle than bulk litter, the pads are relatively expensive, and they do not solve the disposal problem. Another substitute for bulk litter is a liquid. Although it controls odor and bacteria, the liquid tends to slosh and spill out of the tray when the tray is removed from the cage.
Come configurations of animal cages provide for a continuous litter tray extending beneath a row of individual cages, and in some cases the manure-receiving trays are slanted to allow stacking of the cages and mechanical scraper blades are provided to push the manure to the end of the tray. Other arrangements provide reciprocating scraper apparatus with cutoff limit switches for cleaning the trays. However, mechanical scrapers inevitably leave a film of semi-dry manure stuck to the litter tray beneath the cages. This film or residue is an ideal culture medium for bacteria, which, being ever present in the tray, inoculate each successive load of manure, thereby generating noxious odors, particularly ammonia, often to the extent of causing poor growth or production by the caged animals.